If you're having problems uploading the photos that you want to to a certain memory, this can be caused by two things:
1) You're not on our Premium subscription and trying to upload photos to a memory that's not a milestone. You will receive an error message saying that you can't upload photos here.
2) You've recently updated to iOS 14 and have not granted us access to all of your photos when the app asked you after the update (which happens pretty quickly, so not your fault at all). This means you're not seeing all folders and/or photos in it when trying to add a photo to a memory. Most likely you're seeing something like this:
SOLUTION to 2): Please go into your iPhone settings, scroll down until you see the Juno logo, tap on it and you will see this:
Tap onto "Photos" and change the setting to all photos, just like this:
Leave it like this, and you should be able to upload whatever photo you have on your phone to your memories in Juno.